1. Technical Field of the Invention
This invention relates to a flat self-opening closure for combipacks as well as for containers and bottle nozzles of all kinds that are to be sealed with sheeting. This especially includes the liquid packings in the form of such combipacks that are made up of foil-laminated paper, in which liquids like milk, fruit juices, other non-alcoholic drinks or also general liquids of the non-food variety are packed. The closure can also be used for combipacks, in which, free-flowing substances, like sugar, powder, a variety of chemicals or similar substances, are stored or packed. This foil-laminated paper is a laminated substance, similar to paper or board web coated with a plastic such as polyethylene and/or aluminum. Normally, the volumes of such packings range from 20 cl to up to two liters or more. Alternatively, the self-opening closure can also be mounted on the containers, such as bottles made of glass or plastic or similar containers which are sealed by a sheeting. Such seals made up of plastic are available in various designs. When meant for a combipack, they form a pouring nozzle with a shoulder protruding radially from its lower edge, which forms a locking flange at this pouring nozzle. The nozzle is threaded externally, on which a threaded cap can be tightened as the closure. Such a self-opening closure is flanged on to the combipack by welding or sticking to the combipack with the lower side of its protruding edge i.e. with the lower side of its flange. The free passage at the lower end of the nozzle is thereafter blocked by the paper and the dense foil of the combipack. In case of a bottle, the pouring nozzle can be screwed or mounted on the mouth of the bottle and on the inside it can be sealed with a foil membrane. The nozzle is threaded on the outside, on which a threaded cap can then be tightened as the closure.
The foil-reinforced paper, passing below the welded or the stuck nozzle or the foil membrane, fastened within the nozzle must be cut, torn open or pressed out for opening, so that the passage is made clear and the liquid or the free-flowing substance can be poured out of the container through the nozzle. For this, a tube is arranged within the nozzle, which is pressed axially downward when the cap is rotated and thereafter starts rotating in the direction of rotation. The lower end of the tube is provided with one or more piercing or cutting teeth. In this way, the tube is meant to cut out a disc of the foil-reinforced paper or the foil membrane running below it, owing to its axial downward and subsequent rotational movement.
2. Description of the Prior Art
The common self-opening closure comprises of a pouring nozzle, which can be mounted tightly on a combipack or on a container- or a bottle nozzle, which is to be sealed by a foil, a related rotating cap and a self-opening tube arranged within the pouring nozzle, which can be set in motion by the rotating cap. The latest designs have a self-opening tube with at least one individually combined piercing or cutting element at its lower end and away from it. This self-opening tube, the pouring nozzle, as well as the rotating cap, are provided with guides and force transmitters, which coordinate with one another in such a manner that when the rotating cap is rotated for the first time in the direction of opening, the self-opening tube can be pushed first in the pouring nozzle axially downward without rotation and can then be rotated on its axis without any axial movement.
However, if the self-opening tube shows only one individually combined piercing and cutting element, then the tube must have a specific length proportionate to its diameter, which permits its stable guiding in the pouring nozzle in the axial direction, so that tilting is definitely avoided. This necessitates a corresponding overall height of the self-opening closure. Moreover, the self-opening closure must be designed to be relatively sturdy and stable, in order to absorb the reaction forces that originate from a single piercing and cutting element. The guaranteed first opening of such a closure is mostly ensured by installing a safety seal at the lower end of the cap over a number of pre-determined breaking points, whereby the safety seal then bounces over a bulge at the pouring nozzle during the first mounting. For opening the cap for the first time, a great number of individual breaking points must be broken at the same time, which necessitates a correspondingly higher force.